You nailed Apple corners! That alone shows serious dedication. couple random nitpicks: - is the motor driver necessary? for simple vibrations, just a single

You nailed Apple corners! That alone shows serious dedication. couple random nitpicks: - is the motor driver necessary? for simple vibrations, just a single Nch MOSFET between motor negative to ground(low-side switch) should suffice. - there are BLDC vibration motors, because you can(or to eliminate brush sparks) - that button cap doesn't look resistant against external water pressure, if that's a huge issue, but paradoxically waterproof without a drain hole = water container so I can't be sure anyway - color paints flake off. simple acrylic clear, or super ideally two-part urethane, top coat hides it well. I think it's just making flaking of clear layer impossible to notice but it works a lot better than color only. - I think I've seen people mentioning atrocious power saving of ESP32's entire Bluetooth sub-system. it has none or something. - entire watch being sealed from top is right choice, as it allows guts to simply pop out in an unlikely event of battery failure but all aside that watch looks gorgeous.